Circuit arrangement for operating transceivers on an antenna

ABSTRACT

The invention concerns a circuit arrangement for the operation of transmitting and receiving devices (T/R devices) at an antenna. A plurality of T/R devices can be operated for the most part without loss relative to the transmission and receiving powers and almost without mutual influencing of the signal branches of the devices by means of this circuit arrangement. For this purpose, circuit modules for compensation of attenuation (compensators) are disposed between the common antenna and each T/R device. All transmitting and receiving branches of the compensator are connected with the antenna by means of one interconnection unit. The transmitting branches are brought together via passive combiners with the interconnection of an isolator in each case, whereby the output power of their transmission amplifiers is increased in order to equilibrate the attenuation in the combiners. Incoming signals are distributed via splitters to all receiving branches of one frequency band of the compensator, whereby their attenuation is compensated for by an amplifier of the interconnection unit. The interconnection unit has a duplex switch for the separation of the signal paths for each frequency branch.

The invention concerns a circuit arrangement according to the preambleof the principal claim, as it is known from DE 199 13 064 C1. Itconcerns, in particular, a circuit arrangement for the simultaneousoperation of several transmitting and receiving devices (T/R devices) ata common antenna serving for both receiving incoming signals as well asemitting transmitted signals. In this connection, the invention concernsa circuit arrangement in which a circuit module for the compensation(compensation unit) of the attenuation occurring in an HF cableconnecting the antenna with the corresponding T/R device is disposedeach time between the antenna and each T/R device.

In motor vehicles, for example, mobile wireless devices are connectedwith an external antenna on the vehicle by means of a hands-free voicesystem and an HF cable. This serves, on the one hand, for the purpose ofdistancing the driver from the radiation emitted by such a mobilewireless device during the transmitting operation. On the other hand, animproved receiving of incoming signals is achieved by the use of anexternal antenna with respect to the motor vehicle acting as a Faradaycage. Of course, undesired attenuations of the signal occur in the HFcable connecting the mobile wireless device or the hands-free voicesystem with the external antenna. Problems may therefore occur duringtransmitting and/or receiving operations in the mobile wireless devicedue to the narrow tolerances of performance specifications. In order tocompensate for these, it is known to dispose units for the compensationof the attenuation that occurs between the mobile wireless device andthe antenna; these so-called compensators act as compensation modules.In this case, special amplifier units are involved, which provide atleast one transmitting branch with a power amplifier and at least onereceiving branch with a receiving amplifier. Preferably, based on thedetection of a transmission signal emitted by a connected mobilewireless device, the transmitting branch or receiving branch of such acompensator will be switched into the signal path in an alternatingmanner by means of appropriate circuit components. Optionally, suchdevices also have multi-band capacity. They then provide severaltransmitting and receiving branches, whereby transmission signals orreceived signals can be conducted to the transmitting or receivingbranch designed for the corresponding frequency band, depending on thespecific frequency band to which they belong, by means of so-calleddiplex filters. Such a circuit arrangement for compensation ofattenuation is disclosed, for example, by DE 199 13 064 C1, which wasindicated above.

In connection with the increasing extension of communicationsinfrastructures, the continually increasing information need and theincreasing utilization of telematics services, one development isattracting attention, according to which, for example, in motorvehicles, not only dual-band or multi-band-capable mobile wirelessdevices are simultaneously in operation, but also under certaincircumstances, several transmitting and receiving devices are alsooperating. It is not desirable, however, of course, to provide on themotor vehicle an additional external antenna each time for thisplurality of T/R devices. Therefore, transmitting and receiving branchesof several such devices or peripheral devices belonging to them (forexample, a hands-free voice system) are combined on a common antenna. Asfar as we know, this is done according to the prior art by means ofso-called passive combiners and splitters, at which the transmissionsignals of the device are combined or the received signals specific toeach of them are distributed. As long as the devices involve T/R deviceswhich operate in the same frequency band, for example, the combining ofthe transmission signals to the common antenna is accomplished by astar-shaped structure of so-called λ/4 lines. These are lines whichbring about a defined signal delay and thus a phase shift of a signalpassing through them and which are connected together in such a way thatundesired cross-talk of the transmission signal from a transmittingbranch of one device to that of another device is largely prevented by awave quenching. With respect to the combining, for example, of two GSMdevices, an attenuation of approximately 30 dB is obtained between thesedevices in order to prevent them from influencing each other. Thissolution is still unsatisfactory, however, in individual cases relativeto the transmitting operation. Also, a loss of at least 3 dB relative tothe useful signal occurs with the described structure. That is, of theoriginally irradiated power of 2 W of a GSM 900 device, a maximal 1 Wtransmission power reaches the antenna. It is also a disadvantage that astructure with λ/4 lines is not suitable for the operation of so-calleddual-band cell phones, which operate alternatively in the GSM 900 bandor in the GSM 1800 band, since a λ/4 line of the GSM 900 band coveringthe wavelength of the signal, referred to the GSM 1800 band and itsshorter wavelength, acts as a λ/2 line. The attenuation between thesignal branches of two T/R devices guided to such a structure, which isbased on the quenching of waves, therefore cannot be achievedsimultaneously for the GSM 900 and the GSM 1800 operations by means ofsuch an arrangement.

The object of the invention is to provide a circuit arrangement, whichmakes it possible to operate several T/R devices at a common antennalargely without losses with respect to the transmitting and receivingpowers. A mutual influencing of the signal branches of several deviceswill also be avoided. In a preferred design, the circuit arrangementwill also make possible the operation of several devices operating indifferent frequency bands.

The object is solved by a circuit arrangement with the features of theprincipal claim. Advantageous embodiments or enhancements of theinvention are given by the subclaims.

In the proposed circuit arrangement, for the simultaneous operation ofseveral T/R devices at a common antenna, circuit modules known in and ofthemselves are disposed for the compensation (compensationunits—compensators) of the attenuation occurring in the HF cableconnecting the antenna with each of the T/R devices. The compensatorprovides at least one transmitting branch with a power amplifier and atleast one receiving branch with a receiving amplifier, which isalternately switched into the signal pathway, depending on whether theT/R device is receiving or transmitting. This is done on the deviceside, also in the known way, by means of a duplexer or HF two-way switchwhich is switched by a selection circuit or a detector circuit detectinga transmission signal of the respective T/R device. According to theinvention, however, all transmitting and receiving branches of thecompensation units or compensators are joined to the antenna by means ofa special interconnection unit, in which, considered in the direction ofsignal flow, all transmission signals to be assigned to a frequency bandand occurring at the outputs of transmission amplifiers of thecompensators are combined at a duplex switch via one or more passivecombining units (borrowed from the English, also denoted passivecombiners) and are guided from this switch over optional additionalfilter units to the antenna. The incoming signals received at theantenna, which are to be introduced into the receiving branches of thecompensators belonging to them according to the frequency band, areguided over the optionally provided additional filter units, the duplexswitch, and by this, separately from the signal path of the transmissionsignals, are guided over an amplifier and a splitter to the inputs ofthe receiving amplifier. With reference to the transmitting branch,between the output of a transmission amplifier and a passive combiner ofthe interconnection unit connected directly to it, a blocking element(isolator) is disposed that will only let pass the transmission signalsof this corresponding transmission amplifier. In addition, the outputpower of all transmission amplifiers of the compensators is increasedcorresponding to the attenuation of the transmission signal that occursat the passive combiners subordinate to them. Due to the separatecompensation of the attenuation occurring in the passive combiners inthe respective transmission amplifiers of the compensation units and dueto the use of isolators, intermodulations between the signal branches ofthe individual compensation units are prevented, i.e., the impinging ofthe outputs of the power or transmission amplifiers with the amplifiedtransmission signals of another transmitting branch is securelyprevented.

This measure is not necessary, however, relative to incoming receivedsignals. Here, the attenuation which occurs at the splitter distributingthe received signal passively to the receiving amplifiers of thecompensators, is compensated for by a common amplifier of theinterconnection unit effective for all receiving branches within onefrequency band, and this amplifier is connected upstream to thesplitter. The circuit arrangement is capable of duplexing due to theillustrated construction, and in fact, this duplexing is independent ofwhether the same is true for the T/R devices themselves that operatetherein. It is hereby possible that one or more T/R devices aretransmitting signals, while simultaneously other T/R devices arereceiving signals, via the same circuit arrangement.

Corresponding to a preferred enhancement of the circuit arrangementaccording to the invention, the compensators have several transmittingand receiving branches on the device side, thus on the side of the T/Rdevices, connected via a diplexer, for amplifying signals of differentfrequency bands. The interconnection unit is formed in a correspondingmanner, whereby the transmission signals amplified by the compensatorsand the received signals guided to them are conducted over differentfrequency branches of the interconnection unit according to theirfrequency band. This measure involves a frequency band switch, aso-called diplexer for at least one of the filter units which issubordinate to the one or more duplex switches of the interconnectionunit in the direction of the antenna, according to this configuration.By means of the diplexer, transmission signals that are conducted overdifferent frequency branches of the interconnection unit are combinedprior to conducting them further to the antenna, and, in an analogousway, incoming signals received are separated from one another. Also, thecomponents of the interconnection unit named in the basic presentationof the circuit arrangement according to the invention are present foreach frequency branch in this embodiment. Accordingly, each frequencybranch of the interconnection unit consists of at least one or morepassive combiners, a duplex switch, a splitter, as well as an amplifierconnected upstream to the splitter. Basically, it is also conceivable toreplace the diplexer by an externally controlled switch-over unit (forexample, by correspondingly designed, i.e., switchable mobile wirelessdevices). Of course, the limitation arises here that T/R devicesoperating in different frequency bands can be basically operated withthe circuit arrangement, but simultaneously each of the devices alwaysoperates only in one frequency band.

According to an embodiment suitable in practice, the interconnectionunit has two frequency branches, wherein these are preferably designedso that the circuit arrangement is suitable for the operation of severalmobile wireless devices to be used in networks with different frequencybands. With respect to the GSM standard used predominantly today formobile wireless transmission, thus for example, mobile wireless devices(cell phones or the like) can be operated by means of the circuitarrangement via an antenna which operates alternatively in the GSM 900network and/or in the GSM 1800 network.

Preferably, the circuit arrangement and optionally also its units ormodules named above, thus, in particular, the compensators and theinterconnection unit are constructed modularly. In such a modulardesign, isolators are integrated between the outputs of the poweramplifier and the passive combiners, preferably into the module thatmakes up the interconnection unit, wherein an isolator is connectedupstream to each input of a passive combiner for the transmissionsignal.

In addition, an advantageous embodiment of the circuit arrangement isgiven by the fact that the power amplifiers of the compensation unitsare realized by means of basic amplifier modules that can be obtainedcommercially. With respect to the requirements of the GSM standard witha transmission power of 2 W in the GSM 900 network or 1 W in the GSM1800 network and the requirement for an increase in output power for thecompensation of the attenuation occurring in one or more passivecombiners, the use of basic modules with an output power of 4 W or 2 W,respectively, is taken into consideration. Insofar as higher outputpowers are necessary for the transmission amplifiers, due to the numberof T/R devices provided maximally for the operation of the circuitarrangement and the related concrete design of the interconnection unit,corresponding output powers can be attained by suitable interconnectionof such basic modules. In this case, the transmission amplifiers for afrequency band are interconnected by so-called 90° hybrids to theoutputs and inputs, each time within one compensation unit, according toone possible configuration of the invention.

With respect to the number of T/R devices maximally operating on oneantenna by means of the circuit arrangement, according to an embodimentof the invention which is suitable in practice, a specifically gradedincrease in the number of components which is necessary for thispurpose, in particular, the number of passive combiners, is provided.The circuit arrangement is accordingly always designed for simultaneousoperation, with respect to number, of a power (combination power)corresponding to 2 T/R devices (combination maximum). This means thatthe circuit arrangement is designed for the simultaneous operation of 2,4, 8, etc. T/R devices. Thus, for example, if 6 T/R devices are to beoperated by means of an embodiment of the circuit arrangement accordingto the invention that is oriented to such a gradation, an embodimentmaking possible the operation of a maximum of 8 T/R devices would beused for this purpose. Each frequency branch of the interconnection unitin the signal path for the transmission signals thus has a number ofpassive combiners that is decreased by 1 when compared to thecombination maximum (thus for the operation of a maximum of 8 T/Rdevices=7 passive combiners), which are wired in circuit with oneanother in a number of cascade steps corresponding to the combinationpower (thus, again with reference to the example of a maximum of 8 T/Rdevices to be operated, 3 cascade steps −2³=8), while the splitters ofthe respective signal path for the signals received divide these signalsinto a number of signal paths corresponding to the combination maximum.Based on the larger number of passive combiners (more precisely, becauseof this and for cascading in the example of embodiment), the attenuationof the transmission power of a T/R device that occurs on them isnecessarily increased. Consequently, the output power of the poweramplifiers of the compensators must be adequately increased, i.e,preferably so that for each combiner or cascade step, the output powerof each power amplifier of a compensation unit is doubled with referenceto the power of a transmission signal of a T/R device conducted over therespective power amplifier.

In the case of an additional filter unit disposed, as discussed above,optionally between a duplex switch—or in the case of amulti-band-capable design between the diplexer—of the interconnectionunit and the antenna, this involves, for example, a harmonic filter.Preferably, an ESD protective unit, which protects the remaining circuitcomponents against electrostatic discharge, is also disposed between aduplex switch or a diplexer and the antenna. With respect to a modularconstruction of the circuit arrangement according to the invention, thesurface* filter and/or the ESD protective unit are preferably componentson the antenna side of a module that forms the interconnection unit.*sic; harmonic?—Trans. note.

The invention will be explained once more in more detail below on thebasis of embodiment examples. In the appended drawings:

FIG. 1: A rough block diagram of the circuit arrangement according tothe invention FIG. 2: A somewhat more detailed block diagram of thecircuit arrangement according to FIG. 1.

FIG. 3: An excerpt from the circuit arrangement according to FIG. 2 inan embodiment for the operation of four transmitting and receivingdevices

FIG. 4: The block diagram corresponding to FIG. 1 in an embodiment forthe operation of four transmitting and receiving devices

FIG. 5: The interconnection of the transmitting branches of two basicmodules for compensators in order to obtain an increased totaltransmission power

FIG. 6: The combination of signal paths by means of λ/4 lines accordingto the prior art.

FIG. 1 shows a rough block diagram of the circuit arrangement accordingto the invention. It involves an example of embodiment for the commonoperation of 2 T/R devices 1, 1′ at an antenna 2. First, as is knownfrom the prior art, a compensation unit 3, 3′ (compensator) for thecompensation of the attenuation occurring in the HF cable connecting theT/R device 1, 1′ with the antenna 2 is provided between each T/R device1, 1′ and the antenna 2. According to the example shown, it involves adual-band-capable compensator 3, 3′ which makes possible operation bothin the GSM 900 and GSM 1800 frequency bands. All transmitting andreceiving branches 5, 5′, 6, 6′, 7, 7′, 8, 8′ of the two compensators 3,3′ are guided to an interconnection unit 4, a more detailed explanationof which will be made on the basis of FIG. 2.

FIG. 2 shows the circuit arrangement according to FIG. 1 also as a blockdiagram, but in a somewhat more detailed representation. In thisrepresentation, the components of compensators 3, 3′ are also given in asomewhat more detailed manner. It can be seen that the two compensators3, 3′ involve so-called dual-band compensators, which make possible theoperation of a dual-band cell phone or the selective operation of a GSM900 or GSM 1800 cell phone 1, 1′, respectively. For this purpose, thetransmitted and received signals on the device side are conducted bymeans of a diplexer 23, 23′. In transmission mode the diplexer 23, 23′assures that a GSM 900 transmission signal is conducted on the 4-Wattamplifier module of the compensator 3, 3′ and a GSM 1800 signal isconducted on its 2-Watt module. HF two-way switches 19, 19′, 20, 20′ aredisposed in each case in the leads of the amplifier modules. These areswitched by means of detectors 21, 21′, 22, 22′ when a transmissionsignal is present on transmitting branch 5, 5′, 6, 6′. In the reproducedrepresentation, all HF two-way switches 19, 19′, 20, 20′ of compensators3, 3′ are connected in such a way that their receiving branches 7, 7′,8, 8′ are switched into the signal path. This corresponds to the basestate of the circuit arrangement, which is thus ready for receivingincoming signals, independently of whether these are GSM 900 or GSM 1800signals. The switching to the transmitting branch 5, 5′, 6, 6′, asalready shown, is conducted each time always only upon detection of atransmission signal. As soon as the transmission signal fails to appear,the two-way switch 19, 19′, 20, 20′ belonging thereto again passes intothe base state. The respective transmitting branches 5, 5′, 6, 6′ of thetwo compensators 3, 3′, namely the transmitting branches 5, 5′ for theGSM 900 frequency band, on the one hand, and the transmitting branches6, 6′ for the GSM 1800 frequency band, on the other hand, are eachconducted on the output side to a passive combiner 9, 11. As is knownfrom the prior art, only the combining of the signal branches isproduced in this case. In order to compensate for the attenuation here,the output powers of the power amplifier are correspondingly increasedin the transmitting branches 5, 5′, 6, 6′ of the compensators 3, 3′, ascan be recognized. The output power of the transmission amplifier forthe GSM 900 band consequently amounts to 4 W instead of the actuallyrequired 2 W and that of the GSM 1800 branch is 2 W instead of therequired 1 W. In order to prevent crosstalk between the transmittingbranches 5, 5′, 6, 6′ of the same frequency band of the two compensators3, 3′, a special blocking filter 15, 15′, 16, 16′, a so-called isolator,is disposed between the output of a transmission amplifier and thepassive combiner 9, 11, respectively, connected to it each time.Corresponding to an already mentioned embodiment of the invention, thisisolator can be a component of interconnection unit 4, or, as in theexample shown, can be disposed each time directly behind the output of apower amplifier. The transmission signals at the passive combiner 9, 11are combined and from here are guided [via] additional filter units 24,25 to antenna 2 by means of the duplex switches 13, 14, which makepossible the duplex capability of the arrangement. In the reversedirection, incoming signals received at antenna 2 are guided via filterunits 25, 24 to the duplex switches 13, 14, and are distributed fromthese via a splitter 10, 12 to the receiving amplifier of thecompensators 3, 3′. An incoming signal that is received thus is appliedto the two HF plug connectors or connectors of the circuit arrangementprovided for connection to the T/R devices 1, 1′, independently offrequency band, as long as one of the two T/R devices (cell phones) 1 or1′ shown in the drawing is not in transmission mode. Of course, anattenuation of the signal is also caused by the splitters 10, 12 in thereceiving path. This can be compensated for, however, by an amplifier17, 18 common to the two compensators 3, 3′, unlike in the transmissionpath 5, 5′, 6, 6′. As can be recognized in the drawing, these amplifiersare connected in front of the respective splitter 10, 12.

The circuit arrangement according to the invention for the operation oftwo T/R devices 1, 1′, which is shown in FIGS. 1 and 2, can also bemodified for the operation of more than two T/R devices 1, 1′, 1″, 1′″while maintaining the basic principle. This possibility of amodification of the circuit arrangement according to the invention isillustrated as indicated by FIG. 3 relative to a use for the operationof more than two T/R devices. As given in the claims and in thepresentation of the solution according to the invention, thetransmitting branches of the compensators 3, 3′, 3″, 3′″ are combined bymeans of one or more passive combiners. The presentation of FIG. 3 thusconcerns an excerpt of the circuit arrangement according to FIG. 2, andstated more precisely, its design in the region of the combiners 9, 9 a,9 b. It concerns a configuration of the circuit arrangement according tothe invention for operation of a maximum of four T/R devices 1, 1′, 1″,1″ in a preferred variant. According to this configuration, thetransmitting branches of the compensators are combined in pairs eachtime.

This is done by means of the cascading of several passive combiners 9, 9a, 9 b in several planes. It is clear here that another plane ofcombiners is made necessary with each doubling of the maximum number ofT/R devices 1, 1′, 1″, 1′″ to be operated according to this variant andthe number of combiners themselves increases correspondingly. It can beseen at the same time that these embodiment variants that are presentedlead to a power series of 2 corresponding grades with respect to themaximum number of T/R devices 1, 1′, 1″, 1′″ to be operated. This meansalso that the desired operation of 6 T/R devices, for example, requiresan embodiment variant of the circuit arrangement according to theinvention that will allow a maximum of 8 T/R devices to be operated.Therefore, the number of necessary cascades 1, 11 of passive combiners9, 9 a, 9 b corresponds to the respective power of 2. This means thatthe operation of two, i.e., 21 T/R devices requires one passive combinerper frequency branch, that of a maximum of 4 T/R devices, on the otherhand, 2 cascades with a total of 3 passive combiners. In this context,the block diagram according to FIG. 1 is presented in FIG. 4 once morefor an embodiment of the circuit arrangement for the operation of fourT/R devices 1, 1′, 1″, 1′″.

As already mentioned, with an increasing number of T/R devices 1, 1″ tobe operated, the necessary transmission power of the power amplifierincreases in the transmitting branches 5, 5′, 6, 6′ of the compensators3, 3′. This is associated with the increasing number of necessarycombiners 9, 9 a, 9 b, 11 and the attenuation that increases in this wayin this circuit part. With respect to the attenuation of an assumed atleast 3 dB per combiner step, a power of 4 W is required therefore forthe interconnection of two compensators 3, 3′ to the outputs of theirpower amplifiers in the GSM 900 band and a power of 2 W is required forthe GSM 1800 band. Consequently, the necessary power for a maximumnumber of 4 T/R devices 1, 1′, 1, 1″ increases to 8 W in the GSM 900band or 4 W in the GSM 1800 band, respectively. According to a preferredembodiment of the invention with a modular design of its components,standard modules with an output power of 2 W are used for providing thisamplifier power. In order to obtain the optionally necessary higherpower of 4 W, 8 W or even 16 W, following these considerations, acorresponding number of these standard modules are interconnected. Thisis done by means of so-called 90° hybrids 27, 28. This point isillustrated by FIG. 5, which shows a transmitting branch 5 with a poweramplifier consisting of base modules.

With respect to the star-shaped circuitry of λ/4 lines, which wasmentioned above several times, this procedure known from the prior artwill be clarified once more by FIG. 6. Accordingly, for example, twotransmitting branches are combined so that they are interconnected viatwo λ/4 lines and are connected via a resistor R of 100 ohms, forexample. In this way, the direct wave is transfered via the resistorbetween the two branches and a wave rotated by 180° to this istransferred over the two λ/4 lines acting as phase shifters. This leadsto a cancellation of the wave each time at the connection points of thetransmitting branches and thus to an isolation of the two branches, sothat, optionally, signals crosstalking from one transmitting branch tothe other are attenuated by approximately 30 dB. The existingdeficiencies in this purely passively acting arrangement have alreadybeen explained and are overcome by the circuit arrangement according tothe invention.

LIST OF REFERENCE NUMBERS USED

-   1, 1′, 1″, 1′″ Transmitting and receiving device (T/R device)-   2 Antenna-   3, 3′, 3″, 3′″ Compensation unit (compensator)-   4 Interconnection unit-   5, 5′ Transmitting branch with power amplifier-   6, 6′ Transmitting branch with power amplifier-   7, 7′ Receiving branch with receiving amplifier-   8, 8′ Receiving branch with receiving amplifier-   9, 9 a, 9 b Passive combiners (combiners)-   10 Splitter-   11 Passive combiners (combiners)-   12 Splitter-   13, 14 Duplex switch-   15, 15′ Isolator-   16, 16′ Isolator-   17, 18 Amplifier-   19, 19′ HF Two-way switch-   20, 20′ HF Two-way switch-   21, 21′ Detector circuit-   22, 22′ Detector circuit-   23, 23′ Diplexer-   24 Diplexer-   25 Harmonic filter-   26 ESD Protective unit-   27, 28 90° Hybrid

1. A circuit arrangement for the simultaneous operation of severaltransmitting and receiving devices (T/R devices) at a common antennaserving both for the receiving of incoming signals as well as for theemission of transmitted signals, in which between the antenna and eachT/R device a compensation unit is disposed each time for thecompensation of the attenuation occurring in an HF cable connecting theantenna with the corresponding T/R device, which provides at least onetransmitting branch with a power amplifier and at least one receivingbranch with a receiving amplifier, whereby depending on whether the T/Rdevice is receiving or is transmitting signals, these branches areconnected on the device side alternately in the signal path by means ofa duplexer or HF two-way switch switched by a selection circuit or adetector circuit detecting a transmission signal of the relevant T/Rdevice, is hereby characterized in that on the antenna side, alltransmitting and receiving branches of the compensation units areconnected with antenna by means of an interconnection unit, in which,considered in the direction of signal flow, all transmission signalsthat arise at the outputs of transmission amplifiers in transmittingbranches of the compensation units and are to be assigned to onefrequency band are interconnected via one or more passive combiners to aduplex switch and are conducted from this switch to antenna and that thereceived signals arriving at antenna and which are to be introduced intothe receiving branches of the compensation units that belong to therespective frequency band, separated via the duplex switches from thesignal path of the transmission signals, are guided via an amplifier anda splitter to the inputs of the receiving amplifier in the receivingbranches, wherein a blocking element that allows to pass only thetransmission signals of the corresponding transmission amplifier isdisposed each time between the output of a transmission amplifier and apassive combiner directly connected with it and the output power of alltransmission amplifiers of the compensation units corresponding to theattenuation of the transmission signal that occurs at the passivecombiners is increased, and wherein the attenuation occurring at thesplitter distributing the received signal passively to the receivingamplifier of compensation units is compensated for by the amplifiers ofthe interconnection unit connected in front of it.
 2. The circuitarrangement according to claim 1, further characterized in thatadditional filter units are disposed between the duplex switches and theantenna.
 3. The circuit arrangement according to claim 1, furthercharacterized in that the compensation units have several transmittingbranches connected in a circuit via a diplexer and receiving branchesfor the amplification of signals of different frequency bands, wherebythe transmission signals amplified by them and the received signalsintroduced into them are conducted over different frequency branches ofthe interconnection unit according to their frequency band and at leastone of the additional filter units involves a frequency band switch(diplexer), at which transmission signals conducted via differentfrequency branches of the interconnection unit are brought together, orsignals that are received are separated from one another, whereby eachfrequency branch of the interconnection unit consists of at least one ormore passive combiners, a duplex switch a splitter as well as anamplifier connected in front of the splitter.
 4. The circuit arrangementaccording to claim 3, further characterized in that the interconnectionunit has two frequency branches.
 5. The circuit arrangement according toclaim 4, further characterized in that it is designed for the operationof several mobile wireless devices operating selectively in the GSM 900network and/or in the GSM 1800 network.
 6. The circuit arrangementaccording to claim 1, further characterized in that the circuitarrangement and optionally its units are constructed as modules.
 7. Thecircuit arrangement according to claim 6, further characterized in thatwith respect to a modular construction of the circuit arrangement, theisolators are components of the interconnection unit, wherein anisolator is connected in front of each input of a passive combiner forthe transmission signal.
 8. The circuit arrangement according to claim6, further characterized in that the power amplifiers of thecompensation units are realized by amplifier basic modules, which,optionally, are interconnected at the outputs and inputs via 90° hybridsfor obtaining the output power necessary for the compensation of theattenuation in the HF cable and the passive combiners, each time withina compensation unit and relative to the transmitting branch for onefrequency band.
 9. The circuit arrangement according to claim 1, furthercharacterized in that it is designed for the simultaneous operation ofT/R devices (combination maximum) corresponding to a power (combinationpower) of 2 with respect to number, wherein each frequency branch of theinterconnection unit has a number of passive combiners decreased by 1when compared to the combination maximum in the signal pathway for thetransmission signals, which combiners are wired in circuit with oneanother in a number of cascade steps corresponding to the combinationpower, while the splitters of the respective signal path for the signalsreceived divide these into a number of signal paths corresponding to thecombination maximum and the number of compensation units corresponds tothe combination maximum and wherein for each cascade step, the outputpower of each power amplifier of a compensation unit is doubled relativeto the power of a transmission signal of a T/R device conducted over therespective power amplifier.
 10. The circuit arrangement according toclaim 1, further characterized in that a harmonic filter is disposedbetween a duplex switch or a diplexer of the interconnection unit andthe antenna.
 11. The circuit arrangement according to claim 1, furthercharacterized in that an ESD protective unit protecting the remainingcircuit components against electrostatic discharge is disposed between aduplex switch or a diplexer of the interconnection unit and the antenna.12. The circuit arrangement according to claim 10, further characterizedin that a harmonic filter and/or an ESD protective unit representcomponents of the interconnection unit disposed on the antenna siderelative to a modular construction of the circuit arrangement.
 13. Thecircuit arrangement according to claim 11, further characterized in thata harmonic filter and/or an ESD protective unit represent components ofthe interconnection unit disposed on the antenna side relative to amodular construction of the circuit arrangement.